I assume you have written down KPIs clearly discussed with your manager for the current and previous years. If so..
First gather all data like past year performance, manager's feedback for previous year, his commitment to promotion, performance data and appraisal rating info in sync with KPI's established.
Mail it to him beforehand with a request for a meeting to discuss the same.
At the discussion, put forward your point clearly. If he accepts and offers promotion, well and good, else try to understand his stand point and get all statements recorded.
If higher management is at play, request for a meeting with the concerned person and express your thoughts clearly.
Most organisations will honor commitments unless there is a policy change. If so, understand and thank them for the time and effort. Put this behind you and get back to your best.
If not ask them politely as to what you could have done differently or better to get the promotion.
Upon receiving the feedback sum this up in a mail and send it to all concerned so that they are aware that you have understood the reasons clearly and it will also make them realize not to repeat the mistake again.